There is known an engine provided with a valve device which is capable of varying opening and closing timings of one exhaust valve of a plurality of exhaust valves provided for a combustion chamber with respect to opening and closing timings of another exhaust valve of the plurality of exhaust valves. Patent Document 1 discloses an internal combustion engine provided with plural electromagnetic valves as exhaust valves in the same cylinder. In this internal combustion engine, the difference between the earliest opening timing of an exhaust valve and the latest opening timing of another exhaust valve is larger as the engine rotational speed is lower, thereby suppressing the exhaust sound. Patent Document 2 discloses a valve device varying valve timings of first and second engine valves which are the same type of engine valves provided for a combustion chamber.